Re: Aquatic Plants Digest V1 #53

George Booth writes, Mon, Oct 2:

>Is there possibly a third species of Pennywort?  We have what looks
>like two different species in one of our tanks. One is easily
>identified as H.leucocephala.  The other has the same general
>appearance but with some differences.  The leaves of the H.
>leucocephala have a distinct notch that goes to the petiole whereas
>the other has more of the H. verticillata shape (no distinct notch).
>Because of this, I called the other one H. verticillata for a long
>time.  However, it is a much bigger plant - the leaves get up to 3" in
>diameter and the stem is much thicker and robust than the H.
>During a visit to the Dallas Aquarium (at the Fairgrounds), I saw the
>other plant in two of the freshwater tanks growing in huge tangled
>masses around the top surfaces of the tanks.
>Neither version will take on the appearance of the other if they are
>planted or left floating.
>BTW, I have huge amounts of H. leucocephala if you would like some.
>George Booth, Loveland, Colorado


In the part you quoted, I got my Hydrocotyle species mixed up. H.
leucocephala is the one that ascends to the surface and has vee-shaped cuts
in the leaves.  H. verticillata is the one with horizontal stems and round
leaves---the one that I think is growing in my lawn.  I now have my
favorite book on aquatic plants, The Complete Guide to Water Plants, by
Helmut Muhlberg, by my office computer and, hopefully, I won't make as many
mistakes.  Muhlberg says, p. 180, "Probably a number of untried
[Hydrocotyle] species would be interesting as aquarium plants, e.g. the
European H. vulgaris, or the American H. americana."  He doesn't describe
these two species, but perhaps one or the other is one of those you are

You say that the plant you have been calling H. verticillata has much
bigger leaves and stems than H. leucocephala.  I don't know if this is a
reason to doubt that it is verticillata.  The plants in my lawn appear to
have leaves about the size of my leucocephala, but, perhaps if they were
grown under the conditions you provide, they could get bigger.  On the
other hand, Muhlberg says that the diameter of verticillata leaves is up to
3 cm, which is a lot less than 3 inches.  I assume that the 'other plant'
you saw in the Dallas Aquarium was like the one you have been calling
verticillata.  Did it look like yours?

I am going to get around to pulling up some of the suspected verticillata
growing in my lawn and trying to get it going underwater.  It will be
interesting to see what it looks like.

Thanks for the offer of the leucocephala, but my rescued fragment is doing
fine and is about 8 inches long now.  Sometime I might be interested in
your other species, the 'doubtful verticillata', if my 'possible
verticillata' stays little when I grow it underwater.

Gotta get back to work.  I am swamped.  I wonder if that is why I like to
grow aquatic plants:-).

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174